Skip to main content

Story: Apples and pears

Woolly apple aphid

Image
Woolly apple aphid

The woolly apple aphid (Eriosoma lanigerum) is a major pest of apple and pear trees, forming dense colonies that feed on the plant’s roots, shoots and fruit. The tiny insect is purple-brown, and becomes covered in fluffy white threads as it develops. When it feeds it injects poisons into the plant that cause galls to form. In the 1870s severe infestations nearly destroyed New Zealand’s young apple industry, but an Auckland grower noticed that the Northern Spy variety was resistant to the aphid. Northern Spy was easy to propagate, and it was used as a resistant rootstock to replant their infected orchards.

Using this item

HortResearch

This item has been provided for private study purposes (such as school projects, family and local history research) and any published reproduction (print or electronic) may infringe copyright law. It is the responsibility of the user of any material to obtain clearance from the copyright holder.

All images & media in this story

How to cite this page

John Palmer, Apples and pears – Rootstocks and tree management, Te Ara – the Encyclopedia of New Zealand, https://teara.govt.nz/en/photograph/17255/woolly-apple-aphid (accessed 4 June 2026).

Story by John Palmer, published 1 March 2009.